Give three ions that are isoelectronic with neon. Place these ions in order of increasing size.

Neon (Ne) has an atomic number of 10. This means it has 10 electrons and 10 protons in its neutral state.

To find ions with 10 electrons, we can look at the elements around neon on the periodic table: 1. Sodium (Na) has an atomic number of 11. When it loses an electron to form Na+, it has 10 electrons. 2. Fluorine (F) has an atomic number of 9. When it gains an electron to form F-, it has 10 electrons. 3. Oxygen (O) has an atomic number of 8. When it gains two electrons to form O^2-, it has 10 electrons.

The size of an ion depends on the balance between the attractive force of the protons and the repulsive force among electrons. The higher the charge of an ion, the stronger its attractive force, and the smaller the ion. 1. Na^+ has 11 protons and 10 electrons, and it has a +1 charge. 2. F^- has 9 protons and 10 electrons, and it has a -1 charge. 3. O^2- has 8 protons and 10 electrons, and it has a -2 charge. Since O^2- has the lowest charge (-2), it has the weakest attractive force between protons and electrons, making it the largest of the three ions. Na^+ has the highest charge (+1), leading to a stronger attractive force and a smaller size than F^-. Therefore, the order of increasing size is Na^+, F^-, O^2-.